Apparatus for applying adhesive to spirally taped wire insulation

ABSTRACT

IN WIRE THAT IS INSULATED BY MEANS OF A SPIRALLY APPLIED LONGITUDINAL TAPE THE EDGE OF THE TAPE IS SEALED BY APPLYING ADHESIVE THROUGH A BORE THAT OPENS AGAINST THE INSIDE OF THE OPEN FLAP OF THE TAPE.

Aug. 10, 1971 c. G-HAUGEN E'TAL 3,598,670

. APPARATUS FOR APPLYING ADHESIVE TO' SPIRALLY TAPED WIRE INSULATION Filed June 25, 1968 2 Sheets-Sheet 1 /\"\"/1 k CARROLL G. HAUGEN JAMES R. GREENING JOHN J. HILL CHARLES H. DAVIS Aug. 10, 1971 v c. G. HAUGEN EI'AL 3,598,670

APPARATUS FOR APPLYING ADHESIVE TO.SPIRALLY TAPED WIRE INSULATION Filed June 25, 1968 2 Sheets-Sheet 2 y'ivvlgwlolzs CARROLL G. HAUGEN JAMES RGREENING JOHN J. HILL CHARLES H. DAVIS United States Patent 01 fice 3,598,670 APPARATUS FOR APPLYING ADHESIVE T SPIRALLY TAPED WIRE INSULATION Carroll G. Haugen and James R. Greening, Sycamore,

III., John J. Hill, Harrisonville, Mo., and Charles Davis, Shrewsbury, N.J., assignors to Anaconda Wire and Cable Company Filed June 25, 1968, Ser. No. 739,757 Int. Cl. H01b 13/10 US. Cl. 156-54 8 Claims ABSTRACT OF THE DISCLOSURE In wire that is insulated by means of a spirally applied longitudinal tape the edge of the tape is sealed by applying adhesive through a bore that opens against the inside of the open flap of the tape.

BACKGROUND OF THE INVENTION Our invention relates to the application of tape insulation to electric wire. In Burr Pat. 3,271,508 there 1s described a telephone cable comprising conductors with paper tape insulation applied, not helically, as was previously known, but with a longitudinal spiral wrap having an outside edge running parallel to the conductor. Dies for the application of longitudinal spiral tapes are described in Burr Pats. 3,337,386 and 3,340,113. In application Ser. No. 645,414 filed June 12, 1967 and assigned to the assignee of the present application there is described a telephone conductor having the longitudinal edge of the paper tape adhesively bonded to the underlying tape wrap, but with a border of the edge remaining unbonded. The present application relates to apparatus having particular utility for applying adhesive to the tele- {phone conductor described in the above-mentioned application.

In sealing the edge of paper-insulated wires of the type for which the present invention is directed, particularly difficult problems have been caused by the extremely small sizes of the wire, the high speed at which it is necessary to apply adhesive, and the dimensional accuracy with which all operations must be performed. We have, by our invention, met the objectives of an apparatus capable of reliable performance at high speed. Our apparatus is also capable of handling very small wires and narrow tapes. Furthermore our apparatus is self-purging so that it is essentially free from stoppage due to adhesive clogging. And our apparatus is capable of applying a fine line of adhesive to the edge of a narrow tape While leaving a fine border free from adhesive.

SUMMARY Our apparatus will continuously seal the longitudinal edge of an insulating tape that is spirally applied around an advancing wire. The sealing operation is performed as the wire emerges from a tape wrapping die. This apparatus comprises wedge means in alignment with the die separating a longitudinal edge of tape from the wire and a tubular wall defining an adhesive supplying bore that opens against the separated edge of the tape facing the wire. It also comprises means connecting a supply of adhesive to the bore and pressure means urging adhesive through the bore.

Preferably the tubular wall terminates within the wedge means and our apparatus also comprises a roll mounted between the die and the wedge means. The wire is urged against the surface of the roll so as to lift the tape edge away from the Wire. Preferably the roll is adjustably tiltable around an axis normal to the line of advance of the 3,598,670 Patented Aug. 10, 1971 wire, and preferably also our apparatus comprises a pin that fits within the bore, valve means to seal the bore from the supply of adhesive, with the pin purging the bore when the valve means is closed. Our wedge means is preferably mounted on a cradle adjustable around the axis of advance of the wire to accommodate changes in the circumferential position of the tape edge.

Our apparatus comprises a wedge-block mounted adjacent to the line of advance of the wire, with walls in the block that define a channel confining the Wire. One wall of the channel defines Wedge means separating a longitudinal edge of the tape from the wire and a shoulder in the block parallel to the channel abuts the edge of the tape, thus regulating the width of the edge and the width of the border free from adhesive. The block is provided with a fine bore that opens at a point in the surface of the block between the channel and the shoulder above mentioned.

In our method of securing the tape it is advantageous that the adhesive is applied to the inside of the lifted edge of tape rather than to the underlying wrap. This permits a more accurate definition of the unadhered border and reduces the chance of adhesive penetrating the wire insulation.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows a pictorial view of the sealing apparatus of our invention.

FIG. 2 shows a view in section of the adhesive applicator of our invention.

FIG. 3 shows an enlarged section of the wedge block of our applicator.

FIG. 4 shows a side view of the block of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1 our sealing apparatus, indicated generally by the numeral 10 is mounted on a table 11 over which is passed a tape-wrapped wire 12 advancing from a heated die 13 wherein the tape, which in the illustrated case is made of paper, is wrapped around the wire and ironed. The wire 12 is urged into a channel 14 (FIG. 3) of a Wedge block 16, which serves as a flaring tool and adhesive applicator, by the pressure of the surface 17 of a freely turning roller 18 and thence passes through a closing die 19 through which it is being drawn by a capstan, not shown. The roller 18 rotates around a stub shaft 21 mounted on a bracket 22 and terminating in a handle 23. The bracket 22 is mounted by means of a pin 24 in a roller mount 26 so that it can be adjusted in angular position on an axis normal to the axis of the wire. The adjustment is easily made by means of the handle 23 and the angle fixed by means of a lock screw 27. The wedge block 16 is mounted on a support member 28 on which is also communicably mounted an air cylinder 29 having hose connections 31, 32 to a compressed air source not shown through selector valves of a known type. The support member 28 is bolted to a cradle 33 supported by journals 34, 35 in standards 36, 37 through which the wire 12 passes, With the result that the cradle can be rotated around the axis of advance of the wire and locked at any desired angle by means of the lock screw 38 for the journal 34 and a matching lock screw, not shown for the journal 35. The closing die 19 and roller mount 26 are also mounted on the cradle 33 so that they remain in alignment with the wedge block 16 as the latter is rotated to adjust for variations in the angle of tape 39 (FIG. 3) on a conductor 41. When the wire 12 leaves the die 13 the paper tape 39 has been ironed down in a tight spiral around the conductor 41. As explained in Pat. 3,337,386, referred to above, the

conductor 41 is very small being usually from 26 to 19 A.W.G. (American Wire Gage), equivalent to 0.016 to 0.036 inch in diameter, with tape widths from 0.1875 to 0.4375 inch and tape thickness from 0.0015 to 0.0035 inch. The tape is spiralled with two or more full turns around the wire and when it is considered that the entire width of the tape may be less than k of an inch, as explained, and that when a line of adhesive is applied to the edge of the tape it is desired to maintain a border free from adhesive the delicacy and precision required may be appreciated from a consideration of FIG. 3. Here the wire 12 comprising the conductor 41 and spiralled tape 39 has been pressed into the channel 14 of the block 16 by the roller 18. This pressure has also served to lift a fine edge 42 of the tape from the wire and a line 43 of adhesive is applied to this edge from a supply 44 (FIG. 2) of adhesive being urged through a fine bore 46 in the block 16. A border 47 of the edge 42 however remains free from adhesive, the end of this border being abutted against a shoulder 48 to establish the correct positioning of the tape. Adjustment of this positioning can be made not only by rotating the cradle 33 as hereinbefore mentioned but by changing the angle of the bracket 22. Pushing the handle 23 in the downstream direction has the effect of urging the edge 42 into the shoulder 48. The adhesive 44 is fed into a channel 49 in the member 28 through a hose 51 (FIG. 1) connected through a pressure regulator 52 to a supply source not shown. The adjustment of the regulator 52 will vary with the speed and size of wire being processed but we have found that the maintenance of 2 to 40 pounds per square inch of pressure is required with polyvinyl acetate suspension as the adhesive 44.

To control the flow of the adhesive 44 into the bore 46 a valve seat 53 is cut into a cylindrical recess 54 in the member 28. The recess 54 accommodates a plunger 56 of the air cylinder 29 and a machined plug 57 cut to fit the seat 53 is threaded into the end of the plunger 56. A set screw 58 locks a pin 59 into the plug 57. The pin has a slide fit into the bore 46 and is of such length that when the valve plug 57 is seated the pin purges any adhesive from the bore 46 and when the plunger 56 is retracted the tip of the pin is clear of the bore 46 so as to permit the adhesive 44 to enter the bore through an enlarged passage 61 communicating with the channel 49.

The Wedge block 16 is shown in detailed section in FIG. 3 to have the channel 14 defined by parallel walls 63, 64, the wall 63 forming one face of a wedge-like ridge in the block that separates the edge 42 of the tape away from the main portion of insulated wire. The shoulder 48 parallel to the channel 14 abuts the edge 42 and establishes the width of unadhered border which will correspond to the distance from the shoulder 48 to the opening of the bore 46. The block 16 is provided with a cylindrical neck 68 that fits into the member 28. A circumferential groove 69 supports an O-ring 71 to seal the block 16 against any loss of adhesive. A clamp 72 bolted to the member 28 locks against a ledge 73 of the block 16 to hold it firmly in the member 28.

OPERATION In the operation of our apparatus a leading end of the wire 12 from the die 13 is connected to the capstan (not shown) through the die 19 in a manner that causes the wire to rest in the channel 14. The edge 42 of tape is manually lifted from the wire and laid over the wall 63 so that it abuts the shoulder 48. The capstan is started slowly, and the lock screws 38 and its opposing member and the lock screw 27 are loosened and the cradle 33 and roller 18 are adjusted until the tape continues to advance so that the edge exactly abuts the shoulder 48. The lock screws are then tightened and the cylinder 29 operated to withdraw the pin 59 from the bore 46 and start the flow of adhesive and the capstan brought u to speed. If the adhesive pressure requires a further adjust- 4 ment of the tape position the cradle and roller are again loosened and moved as desired.

We have invented a new and useful apparatus and method of which the foregoing description has been exemplary rather than definitive and for which we desire an award of Letters Patent as defined in the following claims.

We claim:

1. Apparatus for continuously sealing the longitudinal edge of an insulating tape spirally applied around an advancing wire as said wire emerges from a tape wrapping die comprising:

(A) wedge means in alignment with said die separating a longitudinal edge of said tape from said wire,

(B) a tubular wall defining an adhesive supplying bore opening against the separated edge of said tape facing said wire,

(C) closing means downstream of said wedge means pressing said edge and said adhesive against an underlying wrap of said tape,

(D) means connecting a supply of adhesive to said bore, and

(E) pressure means urging said adhesive through said bore.

2. The apparatus of claim 1 wherein said tubular wall terminates within said wedge means.

3. The apparatus of claim 1 comprising a roll mounted between said wrapping die and said wedge means, said wire being urged against the surface of said roll, thereby lifting said edge.

4. The apparatus of claim 3 wherein the axis of rotation of said roll is adjustably tiltable around an axis normal to the line of advance of said wire.

5. The apparatus of. claim 1 comprising a pin closely fitting within said bore, valve means sealing said bore from said supply of adhesive, said pin puurging said bore upon the closing of said valve means.

6. The apparatus of claim 2 comprising a cradle adjustable around the axis of advance of said wire, said wedge means being mounted on said cradle.

7. An apparatus for applying adhesive to longitudinal insulating tape spirally applied around a wire advancing from a taping appartus comprising:

(A) a wedge-block mounted adjacent to the line of advance of said wire,

(B) walls in said block defining a channel confining said wire,

(C) one wall of said channel defining wedge-means separating a longitudinal edge of said tape from said wire,

(D) a shoulder in said block parallel to said channel,

said shoulder abutting said edge of said tape,

(E) a tubular wall defining a fine bore in said block opening between said channel and said shoulder.

8. The method of securing a spirally wrapped longitudinal tape around an advancing wire comprising the steps of continuously spirally wrapping said tape, free from adhesive, around said wire with a longitudinal overlapped seam by means of a taping apparatus, continuously lifting an edge of said tape from said wire emerging from said apparatus, continuously applying a line of adhesive by means of an adhesive applicator directly to the inside surface of said edge and pressing said edge back against the underlying turn of said tape.

References Cited UNITED STATES PATENTS 2,494,050 l/ 1950 Loucks 156-54 3,058,867 10/1962 Plummer et al. 15654X 3,340,113 9/1967 Burr 15654 FOREIGN PATENTS 913,912 5/1954 Germany 15654 VERLIN R. PENDEGRASS, Primary Examiner 

